(HealthDay) -- The health risks associated with being overweight and obese are well publicized, but new research may add another condition to this list: leg lymphedema, pain and swelling due to blockage of the lymph nodes in the groin area.
Lymphedema in the arms traditionally is associated with breast cancer surgery that involves removal of or damage to the lymph nodes. A blockage in the lymphatic system can prevent proper drainage of lymph fluid. As fluid builds up, pain and swelling can occur.
In a letter published in the May 31 issue of the New England Journal of Medicine, Dr. Arin Greene and colleagues at Children's Hospital Boston reported on 15 obese individuals with swelling in both legs. They diagnosed five of these individuals with leg lymphedema, and the cause of the condition was obesity.
"We now believe that obesity is a risk factor for lymphedema if the body-mass index becomes greater than 60," Greene said. "It only seems to affect the legs, but we have not investigated the arms."
Individuals in the study who had a body-mass index (BMI) lower than 54 had normal lymphatic function. The average BMI of the patients with lymphedema was 70; BMI of 30 or greater is considered obese. BMI is a measure of body fat based on an individual's height and weight.
Other risk factors for leg lymphedema include injury to the lymph nodes in the groin because of infection, surgery or radiation. In addition, people can be born with the condition. Regardless of the cause, leg lymphedema can cause pain, swelling and infections.
Although there is no cure for lymphedema, compression and significant weight loss may help relieve the pain and swelling, Greene said.
Lymphedema in the legs manifests itself as swelling, pain, discomfort, tightness in the skin, decreased flexibility and difficulty walking, said Cathy Kleinman-Barnett, a lymphedema specialist at the Lymphedema/Edema Management Program at Northwest Medical Center in Margate, Fla.
"Obesity causes lymphedema because the sheer additional weight puts too much pressure on the lymph nodes in the groin area, compromising the system," she said. "This causes a fluid backup like a clogged drain. Skin can thicken, harden and become red, dry and warm to touch."
It's important to treat the condition, she added, because "it can really interfere with a person's quality of life in a physical and a psychosocial way as people may be less inclined to go out and interact with others."
Kleinman-Barnett said lymphedema therapists can prescribe a program of manual lymphatic drainage, which helps direct lymph flow out of the congested areas. Recommendations on skin care, compression bandaging and exercises also can help, she said.
More than 35 percent of U.S. adults are obese, according to the Centers for Disease Control and Prevention. Obesity already is known to increase the risk of heart disease, diabetes, arthritis and certain types of cancer.
Explore further: MU researchers recommend exercise for breast cancer survivors, lymphedema patients
Get tips for preventing lymphedema at the National Lymphedema Network.